Fix the hash signature algorithm in vfslog.c. Add a utility program to

show the hash signatures for every page of a database file.

FossilOrigin-Name: eaf4de13a63b2294ae575432a022493308a4313a

ext/misc/vfslog.c

@@ -307,21 +307,28 @@ static int vlogClose(sqlite3_file *pFile){
 /*
 ** Compute signature for a block of content.
 **
-** The signature is a hex dump of the first 8 bytes of the block
+** For blocks of 16 or fewer bytes, the signature is just a hex dump of
-** followed by a 64bit hash (expressed in hex) of the entire content.
+** the entire block.
+**
+** For blocks of more than 16 bytes, the signature is a hex dump of the
+** first 8 bytes followed by a 64-bit has of the entire block.
 */
 static void vlogSignature(unsigned char *p, int n, char *zCksum){
   unsigned int s0 = 0, s1 = 0;
   unsigned int *pI;
   int i;
+  if( n<=16 ){
+    for(i=0; i<n; i++) sqlite3_snprintf(3, zCksum+i*2, "%02x", p[i]);
+  }else{ 
     pI = (unsigned int*)p;
     for(i=0; i<n-7; i+=8){
       s0 += pI[0] + s1;
       s1 += pI[1] + s0;
       pI += 2;
     }
-  for(i=0; i<8 && i<n; i++) sqlite3_snprintf(3, zCksum+i, "%02x", p[i]);
+    for(i=0; i<8; i++) sqlite3_snprintf(3, zCksum+i*2, "%02x", p[i]);
-  if( n>8 ) sqlite3_snprintf(18, zCksum+i, "-%08x08x", s0, s1);
+    sqlite3_snprintf(18, zCksum+i*2, "-%08x08x", s0, s1);
+  }
 }
 
 /*
@@ -660,5 +667,3 @@ int sqlite3_register_vfslog(const char *zArg){
   vlog_vfs.base.szOsFile = sizeof(VLogFile) + vlog_vfs.pVfs->szOsFile;
   return sqlite3_vfs_register(&vlog_vfs.base, 1);
 }
-
-

manifest

@@ -1,5 +1,5 @@
-C Add\sext/misc/vfslog.c,\sa\sVFS\sshim\sfor\sunix\sthat\skeeps\sa\slog\sof\smethod\scalls\smade\sby\sSQLite.
+C Fix\sthe\shash\ssignature\salgorithm\sin\svfslog.c.\s\sAdd\sa\sutility\sprogram\sto\nshow\sthe\shash\ssignatures\sfor\severy\spage\sof\sa\sdatabase\sfile.
-D 2013-10-10T13:04:46.705
+D 2013-10-10T13:38:51.770
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 5e41da95d92656a5004b03d3576e8b226858a28e
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -115,7 +115,7 @@ F ext/misc/percentile.c bcbee3c061b884eccb80e21651daaae8e1e43c63
 F ext/misc/regexp.c af92cdaa5058fcec1451e49becc7ba44dba023dc
 F ext/misc/rot13.c 1ac6f95f99b575907b9b09c81a349114cf9be45a
 F ext/misc/spellfix.c 5e1d547e9a2aed13897fa91bac924333f62fd2d9
-F ext/misc/vfslog.c 64f8ff0605ba36fd3e71c5e3b2ea00c55448cbbe
+F ext/misc/vfslog.c 9e66605f1c01ec4f7c1b25d07982e1989d7e2eee
 F ext/misc/vtshim.c babb0dc2bf116029e3e7c9a618b8a1377045303e
 F ext/misc/wholenumber.c 784b12543d60702ebdd47da936e278aa03076212
 F ext/rtree/README 6315c0d73ebf0ec40dedb5aa0e942bc8b54e3761
@@ -1100,6 +1100,7 @@ F tool/mkvsix.tcl f3312df26fd9938a27fa0a845ec96bea84b0c16b
 F tool/offsets.c fe4262fdfa378e8f5499a42136d17bf3b98f6091
 F tool/omittest.tcl 4665982e95a6e5c1bd806cf7bc3dea95be422d77
 F tool/opcodeDoc.awk b3a2a3d5d3075b8bd90b7afe24283efdd586659c
+F tool/pagesig.c d8a672401b593726d5dfcadf1b04d37310e4ef94
 F tool/restore_jrnl.tcl 6957a34f8f1f0f8285e07536225ec3b292a9024a
 F tool/rollback-test.c 9fc98427d1e23e84429d7e6d07d9094fbdec65a5
 F tool/showdb.c 525ecc443578647703051308ad50a93de6ba2c4b
@@ -1122,7 +1123,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P d27b88b8c2705f444f794096c719e6f38a792165
+P 24a827b87666670c56d68a18685f4f712852fa92
-R 5f38dde3b9e8f121e53417dc6f4fda25
+R 50c7090bf0272806264dd351e41bc40a
-U dan
+U drh
-Z f43e38212326572373f5c91a1aac8a3a
+Z e3109387d8d252ace6094f69ea11a6f0

manifest.uuid

@@ -1 +1 @@
-24a827b87666670c56d68a18685f4f712852fa92
+eaf4de13a63b2294ae575432a022493308a4313a

tool/pagesig.c

@@ -0,0 +1,92 @@
+/*
+** 2013-10-01
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Compute hash signatures for every page of a database file.  This utility
+** program is useful for analyzing the output logs generated by the
+** ext/misc/vfslog.c extension.
+*/
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+
+/*
+** Compute signature for a block of content.
+**
+** For blocks of 16 or fewer bytes, the signature is just a hex dump of
+** the entire block.
+**
+** For blocks of more than 16 bytes, the signature is a hex dump of the
+** first 8 bytes followed by a 64-bit has of the entire block.
+*/
+static void vlogSignature(unsigned char *p, int n, char *zCksum){
+  unsigned int s0 = 0, s1 = 0;
+  unsigned int *pI;
+  int i;
+  if( n<=16 ){
+    for(i=0; i<n; i++) sprintf(zCksum+i*2, "%02x", p[i]);
+  }else{ 
+    pI = (unsigned int*)p;
+    for(i=0; i<n-7; i+=8){
+      s0 += pI[0] + s1;
+      s1 += pI[1] + s0;
+      pI += 2;
+    }
+    for(i=0; i<8; i++) sprintf(zCksum+i*2, "%02x", p[i]);
+    sprintf(zCksum+i*2, "-%08x08x", s0, s1);
+  }
+}
+
+/*
+** Open a file.  Find its page size.  Read each page, and compute and
+** display the page signature.
+*/
+static void computeSigs(const char *zFilename){
+  FILE *in = fopen(zFilename, "rb");
+  unsigned pgsz;
+  size_t got;
+  unsigned n;
+  unsigned char aBuf[50];
+  unsigned char aPage[65536];
+
+  if( in==0 ){
+    fprintf(stderr, "cannot open \"%s\"\n", zFilename);
+    return;
+  }
+  got = fread(aBuf, 1, sizeof(aBuf), in);
+  if( got!=sizeof(aBuf) ){
+    goto endComputeSigs;
+  }
+  pgsz = aBuf[16]*256 + aBuf[17];
+  if( pgsz==1 ) pgsz = 65536;
+  if( (pgsz & (pgsz-1))!=0 ){
+    fprintf(stderr, "invalid page size: %02x%02x\n", aBuf[16], aBuf[17]);
+    goto endComputeSigs;
+  }
+  rewind(in);
+  for(n=1; (got=fread(aPage, 1, pgsz, in))==pgsz; n++){
+    vlogSignature(aPage, pgsz, aBuf);
+    printf("%4d: %s\n", n, aBuf);
+  }
+
+endComputeSigs:
+  fclose(in);
+}
+
+/*
+** Find page signatures for all named files.
+*/
+int main(int argc, char **argv){
+  int i;
+  for(i=1; i<argc; i++) computeSigs(argv[i]);
+  return 0;
+}